Industrial tape heads, also known as tape applicators, employ a sharp blade for cutting pressure sensitive adhesive tape in the course of application to a case, such as a cardboard box or carton. OSHA standards require these blades to be covered except when the blade is ready to cut the tape.
Currently, industrial tape heads employ a blade guard that is biased by a torsion spring and a finger (or flag) protruding from the blade guard that follows the contour of the box. This finger is longer than the blade guard and provides a delay for the guard's closing, after the tape has been cut. One disadvantage to the use of the flag(s) to actuate the blade guard is the vulnerability of this projection to be broken if a carton becomes stuck in the carton sealing machine, especially if an operator pulls the carton out of the machine. Another disadvantage occurs when the carton to be sealed has a shallow profile. Here, a flag on an upper tape head and a flag on the lower tape head can interfere with one another. Furthermore, the flags can exert too much counter torque on the arms holding the blade, which creates increased cutting pressure. This increased pressure can contribute to the top flaps of the carton caving inward into the carton, which of course is undesirable. Accordingly, a tape head with a different mechanism for opening and closing a blade guard is needed.